{"id":2059,"date":"2023-06-19T18:07:57","date_gmt":"2023-06-19T10:07:57","guid":{"rendered":"https:\/\/xinchewhd.com.cn\/?p=2059"},"modified":"2023-06-19T18:07:57","modified_gmt":"2023-06-19T10:07:57","slug":"sql%e9%ab%98%e7%ba%a7%e7%af%87%ef%bd%9e%e5%8a%a8%e6%80%81%e4%ba%a4%e5%8f%89%e8%a1%a8","status":"publish","type":"post","link":"https:\/\/xinchewhd.com.cn\/index.php\/mysql\/sql%e9%ab%98%e7%ba%a7%e7%af%87%ef%bd%9e%e5%8a%a8%e6%80%81%e4%ba%a4%e5%8f%89%e8%a1%a8\/","title":{"rendered":"SQL\u9ad8\u7ea7\u7bc7\uff5e\u52a8\u6001\u4ea4\u53c9\u8868"},"content":{"rendered":"
\n

SQL\u52a8\u6001\u4ea4\u53c9\u8868\uff08Dynamic Crosstab\uff09\u662fSQL\u67e5\u8be2\u8bed\u8a00\u4e2d\u7684\u4e00\u79cd\u9ad8\u7ea7\u6280\u672f\uff0c\u53ef\u4ee5\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\uff0c\u5b9e\u73b0\u66f4\u52a0\u76f4\u89c2\u7684\u6570\u636e\u5c55\u793a\u65b9\u5f0f\u3002\u5b83\u5141\u8bb8\u6211\u4eec\u5728\u4e0d\u77e5\u9053\u5217\u540d\u548c\u5217\u6570\u7684\u60c5\u51b5\u4e0b\u52a8\u6001\u5730\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\uff0c\u5e76\u5c06\u5176\u5448\u73b0\u5728\u4e00\u4e2a\u8868\u683c\u4e2d\u3002\u8fd9\u5728\u6570\u636e\u5206\u6790\u548c\u62a5\u8868\u751f\u6210\u65b9\u9762\u975e\u5e38\u6709\u7528\u3002<\/span><\/p>\n

\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u4f7f\u7528SELECT\u8bed\u53e5\u6765\u4ece\u8868\u4e2d\u68c0\u7d22\u6570\u636e\uff0c\u5e76\u4f7f\u7528WHERE\u5b50\u53e5\u6765\u8fc7\u6ee4\u6570\u636e\u3002\u7136\u540e\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528ORDER BY\u8bed\u53e5\u5c06\u6570\u636e\u6309\u7167\u6307\u5b9a\u7684\u5217\u6392\u5e8f\u3002\u4f46\u662f\uff0c\u6709\u4e9b\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u9700\u8981\u5c06\u6570\u636e\u6309\u7167\u4e0d\u540c\u7684\u5217\u8fdb\u884c\u5c55\u793a\u3002\u8fd9\u65f6\u5019\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u9759\u6001\u4ea4\u53c9\u8868\uff0c\u5c06\u6570\u636e\u884c\u8f6c\u6362\u4e3a\u6570\u636e\u5217\u3002\u4f46\u662f\uff0c\u9759\u6001\u4ea4\u53c9\u8868\u9700\u8981\u5728\u67e5\u8be2\u65f6\u6307\u5b9a\u6240\u6709\u8981\u5c55\u793a\u7684\u5217\uff0c\u56e0\u6b64\u4e0d\u592a\u9002\u7528\u4e8e\u6570\u636e\u5217\u6570\u4e0d\u786e\u5b9a\u7684\u60c5\u51b5\u3002\u8fd9\u65f6\u5019\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u52a8\u6001\u4ea4\u53c9\u8868\u3002<\/span><\/p>\n

\u52a8\u6001\u4ea4\u53c9\u8868\u901a\u5e38\u4f7f\u7528\u4ee5\u4e0bSQL\u51fd\u6570\u6765\u5b9e\u73b0\uff1a<\/span><\/p>\n

    \n
  1. \n

    MAX\u51fd\u6570\uff1a\u7528\u4e8e\u83b7\u53d6\u6700\u5927\u503c\u3002<\/span><\/p>\n<\/li>\n

  2. \n

    CASE\u8bed\u53e5\uff1a\u7528\u4e8e\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\u3002<\/span><\/p>\n<\/li>\n

  3. \n

    GROUP BY\u8bed\u53e5\uff1a\u7528\u4e8e\u6309\u7167\u6307\u5b9a\u7684\u5217\u5bf9\u6570\u636e\u8fdb\u884c\u5206\u7ec4\u3002<\/span><\/p>\n<\/li>\n<\/ol>\n

    \u4ee5\u4e0b\u662f\u4f7f\u7528\u52a8\u6001\u4ea4\u53c9\u8868\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\u7684\u793a\u4f8b\u4ee3\u7801\uff1a<\/span><\/p>\n

    SELECT<\/span>
      product,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'January'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> January,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'February'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> February,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'March'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> March,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'April'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> April,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'May'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> May,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'June'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> June,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'July'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> July,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'August'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> August,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'September'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> September,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'October'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> October,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'November'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> November,
      SUM<\/span>(CASE<\/span> WHEN<\/span> month<\/span> = 'December'<\/span> THEN<\/span> sales ELSE<\/span> 0<\/span> END<\/span>) AS<\/span> December
    FROM<\/span> sales
    GROUP<\/span> BY<\/span> product;
    <\/code><\/pre>\n
    \u4e0a\u8ff0\u793a\u4f8b\u4ee3\u7801\u5c55\u793a\u4e86\u5982\u4f55\u5c06\u9500\u552e\u6570\u636e\u8868\u6309\u7167\u4e0d\u540c\u7684\u6708\u4efd\u8f6c\u6362\u4e3a\u5217\u6570\u636e\u3002\u5176\u4e2d\uff0c\u4f7f\u7528\u4e86SUM\u51fd\u6570\u6765\u8ba1\u7b97\u6bcf\u4e2a\u4ea7\u54c1\u5728\u4e0d\u540c\u6708\u4efd\u7684\u9500\u552e\u989d\uff0c\u5e76\u4f7f\u7528CASE\u8bed\u53e5\u5c06\u6708\u4efd\u8f6c\u6362\u4e3a\u5217\u6570\u636e\u3002\u6700\u540e\uff0c\u4f7f\u7528GROUP BY\u8bed\u53e5\u5c06\u6570\u636e\u6309\u7167\u4ea7\u54c1\u8fdb\u884c\u5206\u7ec4\u3002<\/span><\/p>\n
    \u603b\u4e4b\uff0cSQL\u52a8\u6001\u4ea4\u53c9\u8868\u662f\u4e00\u79cd\u975e\u5e38\u6709\u7528\u7684\u6570\u636e\u5c55\u793a\u6280\u672f\uff0c\u53ef\u4ee5\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\uff0c\u4ece\u800c\u5b9e\u73b0\u66f4\u52a0\u76f4\u89c2\u7684\u6570\u636e\u5c55\u793a\u65b9\u5f0f\u3002\u5b83\u901a\u5e38\u4f7f\u7528MAX\u51fd\u6570\u3001CASE\u8bed\u53e5\u3001GROUP BY\u8bed\u53e5\u7b49\u6765\u5b9e\u73b0\u3002\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u52a8\u6001\u4ea4\u53c9\u8868\u6765\u751f\u6210\u62a5\u8868\u3001\u5206\u6790\u6570\u636e\u4ee5\u53ca\u8fdb\u884c\u6570\u636e\u53ef\u89c6\u5316\u7b49\u64cd\u4f5c\u3002<\/span><\/p>\n
    \u52a8\u6001\u4ea4\u53c9\u8868\u6709\u51e0\u4e2a\u4f18\u70b9\u3002\u9996\u5148\uff0c\u5b83\u53ef\u4ee5\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\uff0c\u4ece\u800c\u4f7f\u6570\u636e\u66f4\u52a0\u76f4\u89c2\u548c\u6613\u4e8e\u7406\u89e3\u3002\u5176\u6b21\uff0c\u5b83\u4e0d\u9700\u8981\u4e8b\u5148\u77e5\u9053\u8981\u5c55\u793a\u7684\u5217\u6570\u548c\u5217\u540d\uff0c\u800c\u662f\u5728\u67e5\u8be2\u65f6\u52a8\u6001\u751f\u6210\uff0c\u56e0\u6b64\u53ef\u4ee5\u9002\u7528\u4e8e\u6570\u636e\u5217\u6570\u4e0d\u786e\u5b9a\u7684\u60c5\u51b5\u3002\u6700\u540e\uff0c\u52a8\u6001\u4ea4\u53c9\u8868\u53ef\u4ee5\u5c06\u590d\u6742\u7684\u6570\u636e\u5206\u6790\u548c\u62a5\u8868\u751f\u6210\u53d8\u5f97\u66f4\u52a0\u7b80\u5355\u548c\u65b9\u4fbf\u3002<\/span><\/p>\n
    \u7136\u800c\uff0c\u52a8\u6001\u4ea4\u53c9\u8868\u4e5f\u5b58\u5728\u4e00\u4e9b\u7f3a\u70b9\u3002\u9996\u5148\uff0c\u52a8\u6001\u4ea4\u53c9\u8868\u9700\u8981\u4f7f\u7528CASE\u8bed\u53e5\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\uff0c\u56e0\u6b64\u67e5\u8be2\u8bed\u53e5\u4f1a\u53d8\u5f97\u66f4\u52a0\u590d\u6742\u548c\u96be\u4ee5\u7ef4\u62a4\u3002\u5176\u6b21\uff0c\u52a8\u6001\u4ea4\u53c9\u8868\u751f\u6210\u7684\u5217\u6570\u636e\u53ef\u80fd\u4f1a\u975e\u5e38\u5bbd\uff0c\u4ece\u800c\u5bfc\u81f4\u67e5\u8be2\u7ed3\u679c\u7684\u663e\u793a\u548c\u6253\u5370\u53d8\u5f97\u56f0\u96be\u3002<\/span><\/p>\n
    \u603b\u4e4b\uff0c\u52a8\u6001\u4ea4\u53c9\u8868\u662f\u4e00\u79cd\u975e\u5e38\u5b9e\u7528\u7684\u6280\u672f\uff0c\u53ef\u4ee5\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\uff0c\u5e76\u5b9e\u73b0\u66f4\u52a0\u76f4\u89c2\u7684\u6570\u636e\u5c55\u793a\u65b9\u5f0f\u3002\u867d\u7136\u5b83\u5b58\u5728\u4e00\u4e9b\u7f3a\u70b9\uff0c\u4f46\u5728\u9700\u8981\u5bf9\u6570\u636e\u8fdb\u884c\u5206\u6790\u548c\u62a5\u8868\u751f\u6210\u65f6\uff0c\u52a8\u6001\u4ea4\u53c9\u8868\u4ecd\u7136\u662f\u4e00\u79cd\u975e\u5e38\u6709\u7528\u7684\u5de5\u5177\uff0c\u503c\u5f97\u6211\u4eec\u5b66\u4e60\u548c\u4f7f\u7528\u3002<\/span><\/p>\n
    \u52a0\u6211\u5fae\u4fe1\uff0c\u514d\u8d39\u9762\u8bd5\u8f85\u5bfc\u3001\u5b66\u4e60\u8d44\u6599\u3001\u7b80\u5386\u6a21\u677f\u83b7\u53d6\u3001\u52a0\u5165\u5b66\u4e60\u7fa4\u3002<\/span><\/span><\/section>\n

    <\/p>\n
    <\/mp-style-type><\/p>\n
    \n
    \u672c\u7bc7\u6587\u7ae0\u6765\u6e90\u4e8e\u5fae\u4fe1\u516c\u4f17\u53f7:                 IT\u594b\u6597\u7684\u9752\u5e74              <\/p>\n<\/blockquote>\n<\/div>\n","raw":"","protected":false},"excerpt":{"rendered":"
    SQL\u52a8\u6001\u4ea4\u53c9\u8868\uff08Dynamic Crosstab\uff09\u662fSQL\u67e5\u8be2\u8bed\u8a00\u4e2d\u7684\u4e00\u79cd\u9ad8\u7ea7\u6280\u672f\uff0c\u53ef\u4ee5\u5c06\u884c\u6570\u636e\u8f6c\u6362\u4e3a\u5217\u6570\u636e\uff0c\u5b9e\u73b0\u66f4\u52a0\u76f4\u89c2\u7684\u6570\u636e …<\/p>\n","protected":false},"author":1,"featured_media":2057,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"emotion":"","emotion_color":"","title_style":"","license":"","footnotes":""},"categories":[3],"tags":[],"class_list":["post-2059","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mysql"],"post_thumbnail_image":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050915302-150x150.jpeg","content_first_image":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050917272.png","post_medium_image_300":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050915302-300x300.jpeg","post_thumbnail_image_624":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050915302.jpeg","post_frist_image":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050917272.png","post_medium_image":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050915302-300x300.jpeg","post_large_image":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050915302.jpeg","post_full_image":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050915302.jpeg","post_all_images":[{"imagesurl":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050917272.png","id":"image0"},{"imagesurl":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230528050917272.png","id":"image1"}],"videoAdId":"","listAd":"0","listAdId":"","listAdEvery":6,"total_comments":0,"category_name":"MySQL","post_date":"2023-06-19","like_count":"0","praiseWord":"\u9f13\u52b1","copyright_state":"","excitationAd":"0","rewardedVideoAdId":"","detailAdId":"","detailAd":"0","enterpriseMinapp":"0","audios":[],"postImageUrl":"https:\/\/wp-moto-1258805347.cos.ap-shanghai.myqcloud.com\/2023\/05\/20230519082947553.jpg","avatarurls":[],"related_posts":null,"pageviews":369,"next_post_id":2240,"next_post_title":"52\u6761SQL\u8bed\u53e5\u6027\u80fd\u4f18\u5316\u7b56\u7565\uff0c\u5efa\u8bae\u6536\u85cf","previous_post_id":1724,"previous_post_title":"9\u5927\u8868\u8bbe\u8ba1\u4f18\u5316\u65b9\u6cd5\uff0c\u8ba9 MySQL \u6027\u80fd\u98de\u5347\uff01","_links":{"self":[{"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/posts\/2059","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/comments?post=2059"}],"version-history":[{"count":0,"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/posts\/2059\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/media\/2057"}],"wp:attachment":[{"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/media?parent=2059"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/categories?post=2059"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/xinchewhd.com.cn\/index.php\/wp-json\/wp\/v2\/tags?post=2059"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}